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Title: Multiple Redox Modes in the Reversible Lithiation of High-Capacity, Peierls-Distorted Vanadium Sulfide

Vanadium sulfide VS4 in the patronite mineral structure, is a linear chain compound comprising vanadium atoms coordinated by disulfide anions [S2]2–. 51V NMR shows that the material, despite having V formally in the d1 configuration, is diamagnetic, suggesting potential dimerization through metal-metal bonding associated with a Peierls distortion of the linear chains. This is supported by density functional calculations, and is also consistent with the observed alternation in V-V distances of 2.8 Å and 3.2 Å along the chains. Partial lithiation results in reduction of the disulfide ions to sulfide S2–, including via an internal redox process whereby an electron from V4+ is transferred to [S2]2– resulting in oxidation of V4+ to V5+ and reduction of the [S2]2– to S2- to form Li3VS4 containing tetrahedral [VS4]3– anions. On further lithiation this is followed by reduction of the V5+ in Li3VS4 to form Li3+xVS4 (x=0.5-1), a mixed valent V4+/V5+ compound. Eventually reduction to Li2S plus elemental V occurs. Despite the complex redox processes involving both the cation and the anion occurring in this material, the system is found to be partially reversible between 0 and 3 V. In conclusion, the unusual redox processes in this system are elucidated using amore » suite of short range characterization tools including 51V Nuclear Magnetic Resonance spectroscopy (NMR), S Kedge X-ray Absorption Near Edge Spectroscopy (XANES) and Pair Distribution Function (PDF) Analysis of X-ray data.« less
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [7] ;  [1]
  1. Univ. of Cambridge (United Kingdom)
  2. Univ. of California, Santa Barbara, CA (United States)
  3. Ulsan National Inst. of Science and Technology (UNIST), Ulsan (Korea)
  4. Univ. of Oxford (United Kingdom)
  5. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
  6. Univ. of California, Santa Barbara, CA (United States). Mitsubishi Chemicals Center for Advanced Materials Research Laboratory
  7. Ulsan National Inst. of Science and Technology (UNIST), Ulsan (Korea). Interdisciplinary School of Green Energy
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC02-06CH11357; NSF CNS-0960316; DMR-1121053
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 137; Journal Issue: 26; Journal ID: ISSN 0002-7863
American Chemical Society (ACS)
Research Org:
Univ. of California, Santa Barbara, CA (United States)
Sponsoring Org:
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY lithium-ion battery; conversion mechanism; peierls distortion